After a dvb card driver is unloaded and then loaded again, it is no longer
possible to access the dvr device.
Example:
cat /dev/dvb/adapter0/dvr0
kill with ^C
rmmod cx88-dvb
modprobre cx88-dvb
cat /dev/dvb/adapter0/dvr0
cat: /dev/dvb/adapter0/dvr0: No such device
On kernel 2.6.21, this worked fine. In order to get dvb working again,
it's necessary to unload and reload the dvb-core modules.
I strongly suspect commit 57861b432bda77f8bfafda2fb6f5a922d5f3aef1
is somehow related to this problem.